'\" te
.\"  Copyright 1989 AT&T Copyright (c) 2004, Sun Microsystems, Inc.  All Rights Reserved
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.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH DLCLOSE 3C "Mar 1, 2004"
.SH NAME
dlclose \- close a shared object
.SH SYNOPSIS
.LP
.nf
#include <dlfcn.h>

\fBint\fR \fBdlclose\fR(\fBvoid *\fR\fIhandle\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBdlclose()\fR function decrements the reference count of the supplied
\fIhandle\fR. This \fIhandle\fR represents an executable object file and its
dependencies, acquired from a previous call to \fBdlopen()\fR. A \fIhandle\fR
that is no longer referenced is processed in an attempt to unload any objects
that are associated with the \fIhandle\fR from the current process. An
unreferenced \fIhandle\fR is no longer available to \fBdlsym()\fR.
.sp
.LP
Any finalization code within an object is executed prior to that object being
unloaded. Any routines registered by an object using \fBatexit\fR(3C) are
called prior to that object being unloaded. See NOTES.
.SH RETURN VALUES
.sp
.LP
If the \fIhandle\fR was successfully unreferenced, \fBdlclose()\fR returns
\fB0\fR. If the \fIhandle\fR is invalid, or an error occurred as a result of
unloading an object, \fBdlclose()\fR returns a non-zero value. Additional
diagnostic information is available through \fBdlerror()\fR.
.SH USAGE
.sp
.LP
The \fBdlclose()\fR function is one of a family of functions that give the user
direct access to the dynamic linking facilities. These facilities are available
to dynamically-linked processes only. See the \fILinker and Libraries Guide\fR.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	MT-Safe
.TE

.SH SEE ALSO
.sp
.LP
.BR ld (1),
.BR ld.so.1 (1),
.BR atexit (3C),
.BR dladdr (3C),
.BR dldump (3C),
.BR dlerror (3C),
.BR dlopen (3C),
.BR dlsym (3C),
.BR attributes (7),
.BR standards (7)
.sp
.LP
\fILinker and Libraries Guide\fR
.SH NOTES
.sp
.LP
A successful invocation of  \fBdlclose()\fR does not guarantee that the objects
associated with the \fIhandle\fR are removed from the address space of the
current process. Objects can be referenced by multiple \fIhandles\fR, or by
other objects. An object is not removed from the address space of the current
process until all references to that object are removed.
.sp
.LP
Once an object has been closed by \fBdlclose()\fR, referencing symbols
contained in that object can cause undefined behavior.
.sp
.LP
As part of unloading an object, finalization code within the object is called
\fBbefore\fR the \fBdlclose()\fR returns. This finalization is user code, and
as such, can produce errors that can not be caught by \fBdlclose()\fR. For
example, an object loaded using \fBRTLD_LAZY\fR that attempts to call a
function that can not be located, results in process termination. Erroneous
programming practices within the finalization code can also result in process
termination. The runtime linkers debugging facility can offer help identifying
these types of error. See the \fBLD_DEBUG\fR environment variable of
\fBld.so.1\fR(1).
